It is a renovation project of an old building nearly 30 years old. First of all, I put the building in a skeleton state. And I changed the living room which was located on the first floor to the second floor greatly. In urban areas of Japan, houses exist under dense conditions. Therefore, the first floor part is affected by the shade of the surrounding building, it is very sunny. The living room arranged on the second floor has created a sunny and comfortable environment. In addition, stairs and toilets for cats are arranged in each place. The toilet for cats was placed on the ventilation path of the human toilet, and we built up a coexisting environment. In the living room shelves to rise to the beam are installed as a stairway.